My Kohler toilet (1959 model) began leaking between the tank and bowl only when flushed.The spud nut was loose so I tightened it by hand, then re-installed the tank with the old gasket.The leak continued.I purchased a new spud gasket and installed it with the spud nut tightened by hand again.Leak continued. I was able to tighten the nut a little more makeshift tool, but leak continues.Should I buy a spud wrench to get the spud nut as tight as possible or should I apply some grease or other sealant to the spud gasket to make it seal? Is it possible to put the spud nut on before the gasket, or does a gasket recessed to fit over the nut exist?